1. Field of the Invention
The invention relates to a method for producing a shoe component, more particularly to a method for producing a bio-based polymeric shoe component.
2. Description of the Related Art
Ethylene vinyl acetate (abbreviated as EVA) copolymer is a main raw material commonly used in a shoe component of sole pad, midsole or outsole, and is derived from the by products of the petroleum industry. Like other plastic materials, EVA copolymer materials face the problems of increasing cost of petrochemical oil price, non-degradability and environmental pollution at the end of its life cycle.
In order to mitigate the above problems, biomaterials, such as starch, are used to mix with EVA copolymer to produce a bio-based polymeric shoe component. Nevertheless, the biomaterials and EVA copolymer do not have good bonding strength therebetween. Therefore, for better structural strength of the shoe components, the proportion of the biomaterials in admixture with EVA copolymer is low. Furthermore, it is possible to increase the bonding strength between the biomaterials and EVA copolymer by processing those materials under a special condition in higher temperature and pressure or by using modified biomaterials (modified starch) instead.
Because the process conducted at higher temperature and pressure will increase the manufacturing cost, the use of the modified biomaterials is currently more preferable for producing the shoe components.
In order to obtain a bio-based polymeric shoe component with better physical properties, such as structural strength, the parameters controlled in the method for producing the shoe components are also important.